I do think the idea behind snap isn't all about pushing the Linux platform as such forward, but to specifically gain a market advantage to Ubuntu.
Why else is finding documentation for changing the default store so difficult? And I don't think you can even have multiple "repositories" there--quite unlike all other Linux packaging systems out there. (Corrections welcome!)
Another way to check is to
strace cp testfile testfile2
and the sequence in which the message is printed and operations performed can be studied.
It's perhaps a lot to read, but linux tracing tools are worth learning!
They also have a newer model Astro Slide, but it's significantly more expensive and has availability problems. I've had one since Christmas or so, though, and I'm happy with it. CC is fine as well, and indeed the sale seems quite good.
(I used to have their first phone as well, but truly AS would have been a much better first device to bring to the market, there really aren't any fundamental flaws in it in my view.)
As I understand it, these kind of applications depend on being able to perform activities in the background, which is highly limited in iOS for battery efficiency reasons--and maybe for privacy.
Many years ago I was working on a project that shared connectivity details over wifi/bt, and iOS was troublesome also due to the application not being aware of the local bluetooth address.
Possibly similar issues impact other mesh networking applications on the platform.